冷库制冷系统氨工质泄漏扩散与热氨融霜液锤的研究

发布时间：2018-09-09 17:23

【摘要】：氨的一些特殊性质使之成为冷库制冷剂的理想工质,中国约有80%的冷库使用氨作为制冷剂。然而,氨具有一定危险性,冷库制冷系统氨工质的泄漏会引起生产安全和食品安全事故,甚至影响公共安全；冷库热氨融霜过程存在较大安全隐患且往往被人忽视,操作不当就会造成重大泄漏事故。因此,非常有必要针对冷库制冷系统的氨泄漏扩散和热氨融霜过程进行深入研究,找到其中的规律性,从而合理、迅速、及时的采取相应的事故预防及响应措施。本文的研究对于保障中国城市化进程中的食品安全和公共安全将起到重要作用,并将拓宽和深化冷库安全及冷藏链安全管理的研究内涵,推动相关学科与相关技术的发展,为各级政府相关决策提供理论依据。本文首先统计了近些年国内发生的冷库氨泄漏事故,分析了国内外对危险气体泄漏方面的研究历程,并简单介绍了氨气泄漏检测方法；其次,针对制冷系统介绍并分析了氨泄漏扩散及制冷系统发生融霜液锤的原理、不同泄漏源模型、氨气扩散模型及影响扩散的因素；再次,建立事故状态下了氨泄漏模型,运用ANSYS软件模拟了制冷工艺中几种典型热力状态下氨的泄漏扩散过程,通过冷库制冷机房的检测分析,总结了制冷机房内易发生泄漏设备、部件及常态下微量泄漏导致的机房内氨气浓度分布规律；最后,对液锤的破坏作用进行了基本的分析,运用Visual Basic编写了程序,可计算液锤导致管道破裂的最短管道长度,并运用ANSYS软件建立了液锤作用时的管道受力模型,对管道受力进行了模拟分析。结果表明模拟的制冷系统中气态、液态、气液混合物的氨泄漏后的扩散过程与泄漏扩散理论相一致,不同热力状态的氨泄漏后的扩散过程是不同状态参数共同作用的结果；对回气集管的长度提出了设计意见,编程计算得到的长度的管道,经模拟受力分析符合使管道破裂条件。因此,本文对十冷库制氨冷系统的安全运营及维护具有一定的指导意义。
[Abstract]:Ammonia is an ideal refrigerant for refrigerants due to its special properties. About 80% of refrigerants in China use ammonia as refrigerant. However, ammonia has certain danger, the leakage of ammonia working fluid in refrigeration system of cold storage will cause production safety and food safety accidents, and even affect public safety. Improper operation can lead to a major leak. Therefore it is very necessary to study the process of ammonia leakage diffusion and hot ammonia defrosting in cold storage refrigeration system to find out the regularity so as to take the corresponding accident prevention and response measures reasonably quickly and in time. The research in this paper will play an important role in ensuring food safety and public safety in the process of urbanization in China, and will broaden and deepen the research connotation of cold storage safety and cold chain safety management, and promote the development of related disciplines and technologies. To provide theoretical basis for all levels of government decision-making. In this paper, first of all, the ammonia leakage accident in cold storage occurred in recent years is analyzed, the research history of dangerous gas leakage at home and abroad is analyzed, and the detection method of ammonia leakage is briefly introduced. This paper introduces and analyzes the principle of ammonia leakage diffusion and frost thawing fluid hammer in refrigeration system, different leakage source models, ammonia diffusion model and factors affecting the diffusion. Thirdly, the ammonia leakage model is established under the accident state. The process of ammonia leakage and diffusion in several typical thermal conditions of refrigeration process is simulated by using ANSYS software. Through the detection and analysis of refrigerating machine room in cold storage, the leakage equipment in refrigeration machine room is summarized. The distribution law of ammonia concentration in the machine room caused by trace leakage of components and under normal condition is given. Finally, the damage effect of hydraulic hammer is analyzed, and the program is compiled with Visual Basic to calculate the shortest pipe length of pipe rupture caused by hydraulic hammer. The stress model of pipeline under the action of hydraulic hammer is established by using ANSYS software, and the stress of pipeline is simulated and analyzed. The results show that the diffusion process after ammonia leakage in the simulated refrigeration system is consistent with the theory of leakage diffusion. The diffusion process after ammonia leakage in different thermal states is the result of the joint action of different state parameters. The design advice of the length of the return gas collecting pipe is put forward. The pipe with the length obtained by programming is in accord with the condition of the pipeline rupture through the simulated force analysis. Therefore, this paper has a certain guiding significance for the safe operation and maintenance of the ammonia cooling system in the ten cold storage.
【学位授予单位】：哈尔滨商业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB657

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